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Abstract：
Motilin\'s role in the regulation of vascular tone and hemodynamic besides gastrointestinal motility is concerned. This study aimed to investigate the expression of motilin receptors in gastrointestinal arteries and motilin-induced relaxation.
The expression of motilin receptors in the left gastric artery (LGA), superior mesenteric artery (SMA), and inferior mesenteric artery (IMA) of adult dogs (1.5-5 years old) were analyzed by immunochemistry, RT-PCR, and western blotting. Motilin\'s effects on the gastrointestinal arteries were evaluated in a multi-wire myograph system.
Immunohistochemical staining showed that motilin receptor was expressed on the membranes of endothelial cells with the fluorescence intensity LGA > SMA > IMA (P < 0.01). The motilin receptor\'s mRNA and protein expression levels shared the same distribution patterns as it in fluorescence intensity (P < 0.01). In isolated LGA preparations precontracted with U46619 (a thromboxaneA2 analog), motilin induced a concentration-dependent relaxation, and the EC50 was 8.8 × 10-8 ± 0.9 × 10-8 M. Motilin-induced relaxation on the three arteries also shared the same pattern as it in fluorescence intensity (P < 0.01) and inhibited by denuded-endothelium and GM-109 (a motilin receptor antagonist) but not by atropine (a muscarinic receptor antagonist).
Motilin receptors are expressed differentially on the membranes of endothelial cells in dog gastrointestinal arteries with a significantly high expression in the LGA. Motilin-induced relaxation is endothelium- and motilin receptor-dependent. The motilin receptor expressed on the endothelial cell membrane of the LGA is the molecular basis for motilin regulating gastric blood flow under physiological conditions in dogs.
The expression of motilin receptors in the left gastric artery (LGA), superior mesenteric artery (SMA), and inferior mesenteric artery (IMA) of adult dogs (1.5-5 years old) were analyzed by immunochemistry, RT-PCR, and western blotting. Motilin\'s effects on the gastrointestinal arteries were evaluated in a multi-wire myograph system.
Immunohistochemical staining showed that motilin receptor was expressed on the membranes of endothelial cells with the fluorescence intensity LGA > SMA > IMA (P < 0.01). The motilin receptor\'s mRNA and protein expression levels shared the same distribution patterns as it in fluorescence intensity (P < 0.01). In isolated LGA preparations precontracted with U46619 (a thromboxaneA2 analog), motilin induced a concentration-dependent relaxation, and the EC50 was 8.8 × 10-8 ± 0.9 × 10-8 M. Motilin-induced relaxation on the three arteries also shared the same pattern as it in fluorescence intensity (P < 0.01) and inhibited by denuded-endothelium and GM-109 (a motilin receptor antagonist) but not by atropine (a muscarinic receptor antagonist).
Motilin receptors are expressed differentially on the membranes of endothelial cells in dog gastrointestinal arteries with a significantly high expression in the LGA. Motilin-induced relaxation is endothelium- and motilin receptor-dependent. The motilin receptor expressed on the endothelial cell membrane of the LGA is the molecular basis for motilin regulating gastric blood flow under physiological conditions in dogs.
摘要：
胃动素在调节血管张力和血流动力学方面的作用以及胃肠动力方面的作用备受关注。本研究旨在探讨胃动素受体在胃肠动脉中的表达及胃动素诱导的舒张作用。
胃动素受体在胃左动脉（LGA）中的表达，肠系膜上动脉（SMA），和成年犬（1.5-5岁）的肠系膜下动脉（IMA）通过免疫化学分析，RT-PCR,和西方印迹。在多线肌电图系统中评估胃动素对胃肠动脉的影响。
免疫组织化学染色显示，内皮细胞膜上表达胃动素受体，荧光强度为LGA>SMA>IMA（P<0.01）。胃动素受体的mRNA和蛋白质表达水平与荧光强度具有相同的分布模式（P<0.01）。在用U46619（血栓烷A2类似物）预收缩的分离的LGA制剂中，胃动素诱导浓度依赖性松弛，EC50为8.8×10-8±0.9×10-8M。胃动素诱导的三动脉舒张在荧光强度上也具有相同的模式(P<0.01)，并被剥脱内皮和GM-109(胃动素受体拮抗剂)抑制，但不被阿托品(毒蕈碱受体拮抗剂)抑制。
胃动素受体在狗胃肠动脉的内皮细胞的膜上差异表达,在LGA中显著高表达。胃动素诱导的松弛是内皮和胃动素受体依赖性的。LGA的内皮细胞膜上表达的胃动素受体是在狗的生理条件下胃动素调节胃血流量的分子基础。
胃动素受体在胃左动脉（LGA）中的表达，肠系膜上动脉（SMA），和成年犬（1.5-5岁）的肠系膜下动脉（IMA）通过免疫化学分析，RT-PCR,和西方印迹。在多线肌电图系统中评估胃动素对胃肠动脉的影响。
免疫组织化学染色显示，内皮细胞膜上表达胃动素受体，荧光强度为LGA>SMA>IMA（P<0.01）。胃动素受体的mRNA和蛋白质表达水平与荧光强度具有相同的分布模式（P<0.01）。在用U46619（血栓烷A2类似物）预收缩的分离的LGA制剂中，胃动素诱导浓度依赖性松弛，EC50为8.8×10-8±0.9×10-8M。胃动素诱导的三动脉舒张在荧光强度上也具有相同的模式(P<0.01)，并被剥脱内皮和GM-109(胃动素受体拮抗剂)抑制，但不被阿托品(毒蕈碱受体拮抗剂)抑制。
胃动素受体在狗胃肠动脉的内皮细胞的膜上差异表达,在LGA中显著高表达。胃动素诱导的松弛是内皮和胃动素受体依赖性的。LGA的内皮细胞膜上表达的胃动素受体是在狗的生理条件下胃动素调节胃血流量的分子基础。
